From a8e5f2250026c4260bb13fddf696acb7f9322b77 Mon Sep 17 00:00:00 2001 From: Angel Date: Sun, 29 Jan 2023 06:23:45 -0500 Subject: [PATCH] LF-RFID: add CRC calculation to paradox protocol (#2299) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-authored-by: Angel Co-authored-by: あく --- lib/lfrfid/protocols/protocol_paradox.c | 45 ++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 5 deletions(-) diff --git a/lib/lfrfid/protocols/protocol_paradox.c b/lib/lfrfid/protocols/protocol_paradox.c index 7e029f1d..26c9b55d 100644 --- a/lib/lfrfid/protocols/protocol_paradox.c +++ b/lib/lfrfid/protocols/protocol_paradox.c @@ -136,17 +136,45 @@ LevelDuration protocol_paradox_encoder_yield(ProtocolParadox* protocol) { return level_duration_make(level, duration); }; +static uint8_t protocol_paradox_calculate_checksum(uint8_t fc, uint16_t card_id) { + uint8_t card_hi = (card_id >> 8) & 0xff; + uint8_t card_lo = card_id & 0xff; + + uint8_t arr[5] = {0, 0, fc, card_hi, card_lo}; + + uint8_t manchester[9]; + + bit_lib_push_bit(manchester, 9, false); + bit_lib_push_bit(manchester, 9, false); + bit_lib_push_bit(manchester, 9, false); + bit_lib_push_bit(manchester, 9, false); + + for(uint8_t i = 6; i < 40; i += 1) { + if(bit_lib_get_bit(arr, i) == 0b1) { + bit_lib_push_bit(manchester, 9, true); + bit_lib_push_bit(manchester, 9, false); + } else { + bit_lib_push_bit(manchester, 9, false); + bit_lib_push_bit(manchester, 9, true); + } + } + + uint8_t output = bit_lib_crc8(manchester, 9, 0x31, 0x00, true, true, 0x06); + + return output; +} + void protocol_paradox_render_data(ProtocolParadox* protocol, FuriString* result) { uint8_t* decoded_data = protocol->data; uint8_t fc = bit_lib_get_bits(decoded_data, 10, 8); uint16_t card_id = bit_lib_get_bits_16(decoded_data, 18, 16); + uint8_t card_crc = bit_lib_get_bits_16(decoded_data, 34, 8); + uint8_t calc_crc = protocol_paradox_calculate_checksum(fc, card_id); furi_string_cat_printf(result, "Facility: %u\r\n", fc); furi_string_cat_printf(result, "Card: %u\r\n", card_id); - furi_string_cat_printf(result, "Data: "); - for(size_t i = 0; i < PARADOX_DECODED_DATA_SIZE; i++) { - furi_string_cat_printf(result, "%02X", decoded_data[i]); - } + furi_string_cat_printf(result, "CRC: %u Calc CRC: %u\r\n", card_crc, calc_crc); + if(card_crc != calc_crc) furi_string_cat_printf(result, "CRC Mismatch, Invalid Card!\r\n"); }; void protocol_paradox_render_brief_data(ProtocolParadox* protocol, FuriString* result) { @@ -154,8 +182,15 @@ void protocol_paradox_render_brief_data(ProtocolParadox* protocol, FuriString* r uint8_t fc = bit_lib_get_bits(decoded_data, 10, 8); uint16_t card_id = bit_lib_get_bits_16(decoded_data, 18, 16); + uint8_t card_crc = bit_lib_get_bits_16(decoded_data, 34, 8); + uint8_t calc_crc = protocol_paradox_calculate_checksum(fc, card_id); - furi_string_cat_printf(result, "FC: %03u, Card: %05u", fc, card_id); + furi_string_cat_printf(result, "FC: %03u, Card: %05u\r\n", fc, card_id); + if(calc_crc == card_crc) { + furi_string_cat_printf(result, "CRC : %03u", card_crc); + } else { + furi_string_cat_printf(result, "Card is Invalid!"); + } }; bool protocol_paradox_write_data(ProtocolParadox* protocol, void* data) {